Numerous components within a vehicle, i.e., instrument panel, seats, arm rests, etc, absorb a significant amount of solar energy. The most prevalent of these components in this respect is the instrument panel, i.e., IP or dash board, which typically contains an outer layer of polyvinyl chloride (PVC), or like material, having a high energy absorption coefficient and a low thermal conductivity rate. As such, an instrument panel exposed to solar energy, even over a short period of time, may reach temperatures in the 70° C. to 90° C. range during temperate days, especially in areas of high solar intensity, for example in the Southern and Southwestern parts of the United States, in dessert climates like the Middle East and in tropical climates like Brazil.
Thermal absorption by the instrument panel raises several design issues or problems within the vehicle. First of all, the absorbed solar heat puts severe thermal requirements on the material used to make the instrument panel, for example, extreme heat and daily thermal cycling may result in the drying and cracking of the instrument panel and in the fading of the instrument panel color. Damage to the instrument panel requires additional material costs with regard to design and replacement considerations. Second, heat sensitive electronic equipment positioned adjacent to and within the instrument panel may be damaged by the extreme heat and thermal cycling of the instrument panel material, resulting in additional electronics costs with regard to design and replacement considerations. Third, heating of the instrument panel generally results in some level of volatile organic compound release into the vehicle cabin (often associated with an unpleasant smell and in some cases discomfort and nausea). Fourth, release of the absorbed heat from the overheated instrument panel often results in a degrading of the passenger's thermal comfort, especially since the heat often radiates directly at and into the passengers upper body and head. Finally, and perhaps most importantly, thermal absorption puts a significant load on the vehicle's air conditioning system. Studies suggest that an air conditioner compressor, in a temperate part of the United States, must overcome an average of 500 watts of energy to accommodate the heat release from an overheated instrument panel. This increased consumption of energy requires a corresponding increase in fuel consumption by the vehicle and comes with a concomitant increase in the vehicle's emissions. Taken together, the issues associated with solar absorption by the instrument panel and other internal components represent a significant problem in the design and manufacture of a vehicle.
As noted above, air conditioning is one of the prevalent means for overcoming the increased heat associated with an overheated instrument panel. However, the instrument panel has an extremely low thermal conductivity rate, resulting in a very inefficient cooling of the instrument panel. More recently, a blower was integrated into an instrument panel for actively pumping cool air over the overheated surface of the dash board. Although this solution concentrates on cooling the instrument panel and is likely more effective than a passenger compartment air conditioner, it still requires active energy use and hence added fuel consumption and emissions by the vehicle.
Several recent attempts have been made to integrate more passive cooling techniques into the passenger compartment of a vehicle, including installing an energy absorbing windshield and integrating heat pipes into the roof of a vehicle for transfer of the solar energy hitting the roof of the vehicle to the undercarriage of the vehicle. Other attempts have been made by integrating both active and passive cooling techniques into the cooling of an automobile steering wheel and passenger seat. However, neither approach has efficiently abrogated instrument panel overheating and its concomitant problems.
Against this backdrop the present invention has been developed.